Answer this question truthfully
### Question: Who is at highest risk for Progressive multifocal leukoencephalopathy ?
### Response: Anyone with a weakened immune system, however, are at greater risk of developing PML. Causes of a weakened immune system include:
AIDS (less common now because of better AIDS treatments) Certain medications used to treat multiple sclerosis, rheumatoid arthritis, and related conditions Leukemia and lymphoma